1. Field of the Invention
The present invention relates generally to radio communication effected using impulse radio. More particularly the present invention provides an apparatus and method for managing luggage handling using impulse radio communications. The apparatus and method of the present invention are particularly useful in managing luggage handling in a facility, such as an airline, train, bus or other similar terminal, a hotel or any facility at which owner-passengers check luggage at a first locus for later retrieval at a second locus.
2. Related Art
Recent advances in communications technology have enabled an emerging, revolutionary ultra wideband technology (UWB) called impulse radio communications systems (hereinafter called impulse radio).
Impulse radio was first fully described in a series of patents, including U.S. Pat. Nos. 4,641,317 (issued Feb. 3, 1987), U.S. Pat. No. 4,813,057 (issued Mar. 14, 1989), U.S. Pat. No. 4,979,186 (issued Dec. 18, 1990) and U.S. Pat. No. 5,363,108 (issued Nov. 8, 1994) to Larry W. Fullerton. A second generation of impulse radio patents include U.S. Pat. No. 5,677,927 (issued Oct. 14, 1997) to Fullerton et al; and U.S. Pat. No. 5,687,169 (issued Nov. 11, 1997) and U.S. Pat. No. 5,832,035 (issued Nov. 3, 1998) to Fullerton. These patent documents are incorporated herein by reference.
Uses of impulse radio systems are described in U.S. patent application Ser. No. 09/332,502, entitled, “System and Method for Intrusion Detection Using a Time Domain Radar Array,” and U.S. patent application Ser. No. 09/332,503, entitled, “Wide Area Time Domain Radar Array,” both filed Jun. 14, 1999, both of which are assigned to the assignee of the present invention, and both of which are incorporated herein by reference.
Basic impulse radio transmitters emit short pulses approaching a Gaussian monocycle with tightly controlled pulse-to-pulse intervals. Impulse radio systems typically use pulse position modulation, which is a form of time modulation where the value of each instantaneous sample of a modulating signal is caused to modulate the position of a pulse in time.
For impulse radio communications, the pulse-to-pulse interval is varied on a pulse-by-pulse basis by two components: an information component and a pseudo-random code component. Unlike direct sequence spread spectrum systems, the pseudo-random code for impulse radio communications is not necessary for energy spreading because the monocycle pulses themselves have an inherently wide bandwidth. Instead, the pseudo-random code of an impulse radio system is used for channelization, energy smoothing in the frequency domain and for interference suppression.
Generally speaking, an impulse radio receiver is a direct conversion receiver with a cross correlator front end. The front end coherently converts an electromagnetic pulse train of monocycle pulses to a baseband signal in a single stage. The data rate of the impulse radio transmission is typically a fraction of the periodic timing signal used as a time base. Because each data bit modulates the time position of many pulses of the periodic timing signal, this yields a modulated, coded timing signal that comprises a train of identically shaped pulses for each single data bit. The impulse radio receiver integrates multiple pulses to recover the transmitted information.
In a multi-user environment, impulse radio depends, in part, on processing gain to achieve rejection of unwanted signals. Because of the extremely high processing gain achievable with impulse radio, much higher dynamic ranges are possible than are commonly achieved with other spread spectrum methods, some of which must use power control in order to have a viable system. Further, if power is kept to a minimum in an impulse radio system, this will allow closer operation in co-site or nearly co-site situations where two impulse radios must operate concurrently, or where an impulse radio and a narrow band radio must operate close by one another and share the same band.
In common carrier passenger terminals, such as airline, train, bus or other transportation terminals, or at hotels or other facilities where owner-passengers check luggage at a first locus for later retrieval at a second locus there is a need for reliable and flexible luggage handling. That is, luggage must be routed for appropriate loading for transport. It is absolutely necessary that luggage reach the proper destination, preferably with or before its respective owner-passenger. Most preferably, luggage should travel with its owner-passenger. Flexibility for luggage handling involves such situations in which a gate or other embarkation locus changes, or an owner-passenger's itinerary changes. A luggage handling system must be capable of accommodating such changes while still getting the luggage to the same destination as the owner-passenger before or together with the owner-passenger.
Human resources for sorting, routing, tracking and rerouting luggage have been employed for a long time. Improvements over human resources have been sought to reduce costs (human resources are expensive), to reduce opportunities for human error and to provide flexibility that may be realized when using automatic luggage tracking systems.
Optical reading systems have been touted as serviceable. However, optical reading systems have been foiled by folded, bent, torn or otherwise unreadable tags. Other line-of-sight or near-range systems have included resonant tags that may excite a reader at ranges of approximately one meter. Such systems are at best a partial improvement over human resources, but are not an entire solution.
Radio frequency (RF) tags using amplitude modulation (AM) or frequency modulation (FM) technologies have been proposed, but they are limited in the number of individual luggage pieces that can be discerned. A saturation level is reached rather quickly at which identification signals for respective luggage pieces begin to interfere among each other. Identification information may be broadcast by such AM or FM RF tags, but location information is less reliably obtained from radio signals using such prior art systems.
The present invention provides a duplex communication-capable identification token, such as a tag, for employing impulse radio technology to announce identification and location for a respective luggage item. Such a duplex communication capability enables notification of a respective luggage item identifier tag that a change has occurred which requires rerouting of the respective luggage item. A change that may occasion such a notice may include, for example, a gate change for departure of an aircraft, a flight change for a given owner-passenger, or a change of luggage carousel for luggage collection for an arriving flight or a similar change. The rerouting that may be required to respond to such a change may accommodate a new locus for embarkation for travel, or a new collection locus for an owner-passenger to retrieve his luggage item after debarkation.
A luggage handling system may provide for automatic rerouting from one embarkation/debarkation locus to another such locus. A simpler (and, hence, lower cost) system may simply provide for an alert capability. An alert capability preferably enables an individual luggage item to respond to receiving notice of a change by alerting a human operator that it is a luggage item requiring attention. Such an alerting may be effected by any one or more of several means including, for example, a lighted identification of the luggage tag or a radio communication notice-response to a control station. Such a radio communication notice-response may indicate that special attention is required of a luggage item, and may include the location of the luggage item. The notice-response may be relayed by the central station to a locus near the location of the affected luggage item for intervention by a human operator to effect rerouting. Alternatively, the notice-response may be employed by the luggage handling system to commence an automatic pick-and-place operation to return the luggage item to a transport apparatus for rerouting to a new embarkation/debarkation locus.
One embodiment of the present application contemplates placing a RF tag on an owner-passenger's luggage item while the owner-passenger checks in for a flight at an airport. The check-in procedure employs equipment that effects entering of an identifier code for the RF tag in association with the owner-passenger's name being added to the passenger manifest for his flight. Other information associated with the RF tag identifier and the owner-passenger's identity are the flight number, an embarkation locus for the flight at which luggage is to be loaded, and a debarkation locus at the destination airport for the owner-passenger to retrieve the luggage item.
The debarkation information may be provided to the RF tag after arrival at the destination airport by radio communication link at the destination airport.
In the event that there is a change in any of the parameters entered into the RF tag, the new information may be sent to the RF tag via an RF communication network employing impulse radio technology at the embarkation airport or at the debarkation airport, as appropriate. Changes in flight arrangements may be communicated to the RF tag using the RF communication network if the owner-passenger alters his arrangements.
If the owner-passenger is traveling via an intermediate airport in making a multi-leg journey, the RF tag may be used to indicate its proper new embarkation locus for following the owner-passenger to his ultimate destination. Moreover, if the owner-passenger alters his itinerary en route, the RF tag may be “notified” using the RF communication network and the luggage item may be rerouted to accompany the owner-passenger. This arrangement may be especially useful in situations involving an owner-passenger interrupting (rather than merely altering) his trip at an interim airport. In such a case, the RF tag may be “notified” and transfer of the luggage item may be interrupted to allow the luggage item to remain at the interim airport instead of its being forwarded on to the original ultimate destination airport.
The immediate “notification” capability of the luggage handling system of the present invention would be especially useful in times when massive flight cancellations are imposed, as often occurs during periods of bad weather. The luggage handling system of the present invention will facilitate return of luggage items to their respective owner-passengers in such circumstances.
RF tags may be removed by baggage handlers after arrival at a destination airport and before placing luggage on the carousel from which owner-passengers will retrieve their luggage items. Removed RF tags may be deprogrammed and recycled for use with later owner-passengers. In one embodiment of the present invention, RF tags include a rechargeable power source that may be recharged periodically to ensure their proper performance with later owner-passengers. In an alternate embodiment, lower cost RF tags may be employed that are not removed for recycling.
It would be preferable for a luggage handling system to be able to automatically reroute luggage to a proper embarkation (or debarkation) locus to respond to changes in transportation arrangements of whatever nature. A luggage handling system should at least identify luggage pieces affected by changes in transportation arrangements (e.g., gate changes or flight changes) to facilitate intervention by human operators to implement an appropriate response to such a change.
There is a need for a luggage handling system that can automatically route individual luggage pieces to proper embarkation or debarkation loci appropriate for accompanying respective owner-passengers of the luggage pieces.
There is a need for a luggage handling system that can react to changes in transportation arrangements to effect proper delivery of luggage pieces to loci appropriate for retrieval of luggage items by respective owner-passengers of the luggage pieces.